Watercraft Inspection Steward Field Guide
A FIELD GUIDE TO The Lower Hudson Valley’s
Aquatic Invasive Species NOT FOR DISTRIBUTION
Samantha Epstein Invasive Species Program Coordinator Hudson River Sloop Clearwater, Inc
Table of Contents
Overview………………………………………….…………………………………………………………………………………………………………………………………………………..1 New AIS Regulations……………………………………………………..……………………………………………………………………………………………………………………..1 New York Prohibited Species……………………………………………..…………………………………………………………………………………………………………….....1
Spread Prevention/Clean Boating Practices…………………………….……………………………………………………………………………………………………………..2
Aquatic Invertebrates Chinese Mystery Snail………………………………………………………………………………………………………………………………………………………………3 Asian Clam……………………………………………………………………………………………………………………………………………………………………………….4 Zebra Mussel………………………………………………………………..………………………………………………………………………………………………………….5 Spiny Water Flea…………………………………………………….……………………………………………………………………………………………………..…………6
Chinese Mitten Crab….….……………………………………………….………………………………………………………………………………………………………….7 Asian Shore Crab………….………………………………………….………………………………………………………………………………………………………………8 Rusty Crayfish………………..…………………………………………………………………………………………………………………………………………………………9 Fish Goldfish………………………………………………………………………………………………………………………………………………………………………………….10 Common Carp…………………..……………………………………………………………………………………………………………………………………………………11 Northern Snakehead………..…………………………………………………………………………………………………………………………………………………….12 Oriental Weatherfish……….…………………………………………………………………………………………………………………………………………………….13 Round Goby……………………………………………………………………………………………………………………………………………………………………………14 Sea Lamprey...... …………………………………………………………….………………………………………………………………………………………….15
Submersed Aquatic Vegetation Fanwort…………………………………………………………………….……………………………………………………………………………………………………………16
Brazilian Elodea……….…………………………………………..…………………………………………………………………………………………………………………17 Hydrilla……….……………………………………………………………..…………………………………………………………………………………………………………..18 Parrot Feather………………………………………………………………………………………………………………………………………………………………………..19
Variable Leaf Milfoil….……..…………………………………………….………………………………………………………………………………………………………..20 Eurasian Water Milfoil……………………………………………………………………………………………………………………………………………………………21
Table of Contents Cont.
Brittle Naiad…….…………………………………………………….……………………………………………………………………………………………………………….22 Curly Leaf Pondweed……………………………………………………………………………………………………………………………………………………………...23
Floating Aquatic Vegetation European Frogbit……………………………………..…………………………………………………………………………………………………………………………….24 Yellow Floating Heart……………………………..………………………………………………………………………………………………………………………………25
Water Chestnut…………….………………..…….…………………………………………………………………………………………………………………………………26
Facultative Species Yellow Iris…………………………………….………….…………………………………………………………………………………………………………………………….27 Purple Loosestrife……………………………..…………..……………………………………………………………………………………………………………………...28 Phragmites……………………………………………………………………………………………………………………………………………………………………………..29
Native Lookalike: American Waterweed/Common Elodea………………………………………………………………………………………………………….....….30
Sources……………………………………………………………………………………………………………………………………….…………………………………………………30-31 Image Credits………………………………………………………………………………………………………………………………..………………………………….……………32-34
General Overview Prohibited Species An invasive species is defined as one that is non-native to the New York State has listed numerous terrestrial and aquatic species as ecosystem, causes harm or has the potential to cause harm to the prohibited and regulated. These new regulations were published in economy, ecology, or to human health, and the species’ harmful September 2014, and became effective in March 2015. The new impacts significantly outweighs its benefits. Some of the invasive regulation (6 NYCRR Part 575 Prohibited and Regulated Invasive species found in the Lower Hudson Region are already widespread, Species) prohibits 69 plants, 15 fish species, 17 aquatic invertebrates, 5 while others can be established, emerging, or still a threat. There are terrestrial and aquatic vertebrates 3 species of algae and also species that are approaching the region, and can be found in cyanobacteria, and more. These prohibited species range from the neighboring regions. mute swan to hydrilla to the spiny water flea.
This field guide does not list all of the species approaching or already in Aquatic Invasive Species now prohibited in NY include: the region. It gives a general overview of the most common species found throughout the area (water chestnut), and species that we are Killer Green Algae Bighead Carp on the lookout for (hydrilla). Didymo Oriental Weatherfish Golden Algae Black Carp New Regulations Fanwort Round Goby A new amendment to Subdivision (i) of § 377.1 of Title 9 NYCRR has Brazilian Waterweed Sea Lamprey been approved by the New York Office of Parks, Recreation, and Hydrilla, Water Thyme Tubenose Goby Historic Preservation that is designed to control the introduction and European Frogbit Tench spread of aquatic invasive species at facilities under OPRHP jurisdiction. Yellow Iris Chinese Mystery Snail Under the newly amended legislation, one must take reasonable Purple loosestrife Japanese Mystery Snail precautions to stop the spread of AIS: Parrot-feather Faucet Snail Summarized: Prior to launching and when leaving the site, the Broadleaf Water-milfoil Spiny Water Flea operator shall inspect for and remove any plant, aquatic life or Broadleaf water-milfoil Fishhook Water Flea animal, or parts thereof, and dispose in designated receptacles or hybrid Asian Clam in such a manner to avoid contact of the material with the Eurasian watermilfoil Suminoe Oyster waterbody. Measures must also be taken before arriving at a new Yellow floating heart Carpet Tunicate site or leaving the current site to drain the watercraft (bilge area, Curly leaf pondweed Zebra Mussel livewells, bait wells, and ballast tanks) – Effective Nov. 12, 2014 Water chestnut Quagga Mussel
NY Senate also amended the navigation law to include a section about Northern Snakehead Chinese Mitten Crab universal AIS signage at launches. Bullseye Snakehead Asian Shore Crab Summarized: The Department of Environmental Conservation will Giant Snakehead Bloody Red Shrimp design and establish universal signage which will be posted at any Walking Catfish Rusty Crayfish access point to the navigable waters of the state relating to the Western Mosquitofish New Zealand Mud Snail threat and mitigation of AIS. Owners of each public boat launch Eastern Mosquitofish Vined Rapa Whelk shall conspicuously post the universal sign at each public boat Largescale Silver Carp Asian Sea Squirt launch in the state Silver Carp Mute Swan Stop Aquatic Hitchhikers
There are many pathways for spreading aquatic invasive species. An invasive species can be introduced for cultural reasons (e.g. food), through accidental introductions (e.g. hitchhiker on boat, ballast water, dumping aquaria species), through the pet and aquarium trade (releasing aquarium pets and plants into a waterbody), bait, waterfowl, and more. The best defense that we have against new introductions is PREVENTION. An important way to prevent one of the biggest AIS pathways – hitchhikers on boats – is by using clean boating practices when entering a new body of water and before leaving a body of water. The three key components to clean boating include:
Clean – Remove all visible mud, plants, fish, animal, organisms, and debris from your boat, trailer, and any equipment that came into contact with the water. Always clean your boat before leaving a body of water. Discard all potential hitchhikers in the proper disposal station when provided, or above the high water line. Drain – Eliminate water from all equipment (motors, live wells, ballast, waders, etc.) before leaving the site. Dry – Dry anything that came into contact with the water. If possible, decontaminate your boat and equipment with hot (<140°F), high pressure water. If this is not an option, allow your boat to dry for at least 5 days before entering new waters.
2
Chinese Mystery Snail Cipangopaludina chinensis/Bellamya chinensis
A FIELD GUIDE TO GUIDE A FIELD Identification
The Chinese mystery snail has large, globose, smooth, and strong shells. The shell can grow 6.5 cm in height, usually has
6-7 convex whorls and the inner coloration is white to pale blue. It exhibits light coloration as a juvenile and olive green, greenish brown, brown, or reddish brown coloration as an
adult. The shell has an oblong-shaped operculum (“trap door”) AIS VALLEY’S HUDSON LOWER THE that displays concentric growth rings. The operculum allows the snail to close the opening of the shell when water conditions become unfavorable or when being attacked by a predator
Impacts
Chinese mystery snail was found to cause declines in growth and abundance of native snail species, likely through Native Range competition for food. They are also less vulnerable to predation by the invasive rusty crayfish due to their larger size The Chinese mystery snail is native to Eastern Russia, China, and thicker shells than native snails. The Chinese mystery snail Japan, Korea, Philippines, Taiwan, and Vietnam. can also reduce algal biomass, which changes the Nitrogen:Phosphorus ratio. They are also a nuisance to water Spread intake pipelines, often clogging the screens and inhibiting the flow of water. Probably introduced through the aquarium trade or as an Chinese mystery snails can also serve as vectors for importation for food markets, the Chinese mystery snail spreads transmitting parasites and diseases, and host some parasites by recreational activities through bait buckets or water holding that can infect humans. areas on boats (ballast, live well, etc.). It can still be introduced
through accidental introductions from aquariums. 3
The Chinese mystery snail is a threat in the Lower Hudson Valley. Asian Clam Corbicula fluminea
TO GUIDE A FIELD Identification
The Asian clam is a freshwater clam with a triangular yellowish brown to black shell with concentric, evenly spaced ridges on the shell surface. They are usually less than 25 mm but can grow up to 65 mm in length. It can be found on numerous substrates including silt, mud, sand, and gravel, and can tolerate sanities of up to 13 ppt for short
periods of time. AIS VALLEY’S HUDSON LOWER THE
Impacts
The Asian clam is highly successful coupling the nutrients in the water column and bottom sediments, filtering out phytoplankton and other particles suspended in the water that are also important food sources for filter-feeding organisms. They also excrete significant amounts of Native Range inorganic nutrients that can, in turn, stimulate algae and macrophyte growth. Asian clams have mass mortality events that occur in the summer, followed by the release of nutrients via decomposition, The Asian clam is native to eastern and southern Asia and was which can also lead to negative water quality effects. The shells create introduced as a food source. new habitat for species that prefer harder substrates (e.g. zebra mussels). Spread
Asian clams are known to colonize intake pipes of water treatment The Asian Clam is hermaphroditic and capable of self-fertilization. systems and power stations. Unlike zebra mussels, the Asian clam It can spawn year round in warmer waters, and can release does not attach to hard substrates. The juvenile clams pass through hundreds of thousands of veligers each day, which are then spread filter screens and settle on the floors of intake pipes where they by water currents and human activity. The veligers and mature reproduce and continue to accumulate in pipes while getting clams are able to attach themselves to boats, trailers, and transported deeper into the system, eventually blocking structures equipment and can be transferred in bait buckets or water with shells, altering flow, and increasing sedimentation rates. compartments including live wells and bilges.
4 The Asian Clam is emerging in the Lower Hudson Valley.
Zebra Mussel Dreissena polymorpha
A FIELD GUIDE TO GUIDE A FIELD Identification
The zebra mussel has a triangular shell with a sharply pointed shell hinge end. The mussel can grow up to 5 centimeters, but most rarely exceed 4 cm. There is a prominent dark and light banding pattern on the shell. It is tan in color with broad, transverse color bands that are
either smooth or zigzag in shape. The mussel attaches to
THE LOWER HUDSON VALLEY’S AIS VALLEY’S HUDSON LOWER THE hard surfaces using byssal threads, which distinguishes this mussel from other similar mussels in the region. The shell’s “D-shape” gives it a straight midventral line and a prominent ridge that allows it to sit flat on its ventral side, unlike other mussel species.
Impact Zebra mussels also clog intake pipes, ship hulls, and more, causing damage to boats and water treatment plants. Zebra mussels were first discovered in the Hudson River in 1991, and by 1992 their densities were reaching over Native Range 100,000 individuals per square meter. In such great The zebra mussel is native to Europe, Russia, Turkey, and Ukraine. densities, they were able to filter all of the water in the freshwater portion of the Hudson every 2-4 days, compared Spread to the native mussels that filtered the water every 2-3 months. This causes a reduction in phytoplankton numbers Female zebra mussels can produce up to one million eggs in a and biomass which limits food for fish larvae, and eventually season. These free-floating veligers can be transported undetected other consumers further up the food chain. Zebra mussel in bait buckets, bilge water, and live wells. The mussels can also colonization can impede fish foraging and can affect survive out of water for up to five days and can easily be spawning fishes. transported to other waterbodies on boats, trailers, and other equipment. 5 The zebra mussel is established in the Lower Hudson Valley. Spiny Water Flea Bythotrephes longimanus (B. cederstroemi)
Identification TO GUIDE A FIELD
Spiny water flea is a carnivorous crustacean similar to the sea monkey, reaching 10-15 mm at maturity. Its long, spiny tail comprises about 2/3 of its body length. The head has one black eye and a pair of sickle-shaped mandibles. The spiny water flea has two swimming antenna behind its head and four pairs of legs used to
catch their prey. AIS VALLEY’S HUDSON LOWER THE
Impacts
The spiny water flea has directly impacted the native, herbivorous zooplankton including the species Daphnia, an important food for many native larval fish species. Native Range This makes the spiny water flea a direct competitor of the larval fish species. With its rapid reproduction, it is Native to the Northern Europe and Asia sometimes able to outcompete them. Spread The spiny water flea is also a nuisance for anglers and fisherman. They attach themselves in gelatinous globs The spiny water flea collects on fishing lines and fishing gear, forming on fishing lines, downriggers, anchor ropes, and fishing jelly-like globs. Eggs are able to survive being dried out and can survive nets. The eggs are able to resist drying and freezing, and on fishing gear for extended periods of time, which is why cleaning can establish a new infestation once entering another your boats and equipment is important. The spiny water flea can also body of water. Eggs can also pass through the digestive spread in water containers on boats, so draining water from bilges, live tracts of fish. Females carrying eggs can be twice their wells, etc. is extremely important. normal weight, and their increased predation is another way for the eggs to disperse. The spiny water flea is approaching the Lower Hudson Valley 6
Chinese mitten crab Eriocheir sinensis
A FIELD GUIDE TO GUIDE A FIELD Identification
The Chinese mitten crab has a distinguished square shaped carapace that can reach 5-7 cm with a maximum carapace of 10 cm. Another distinguishing feature is the hair-like covering on the claws, resembling mittens. The color varies from yellow to
brown, and is rarely purple. AIS VALLEY’S HUDSON LOWER THE Impact
The Chinese mitten crab is an opportunistic omnivore, consuming macroalgae, invertebrates, and fish which can diminish the food sources for the native crabs. Native Range Their burrowing activity can damage dikes and increase river embankment erosion, and can even The Chinese mitten crab is native to southeast Asia, southern China, and cause bank collapses. Chinese mitten crabs have the Korean peninsula. become a nuisance for recreational and commercial anglers by getting entangled in fishing gear, causing Spread damage to fishing nets. They also reproduce and migrate in such high numbers that they can block The Chinese mitten crab is spreading across the world in ballast water water intakes and drainage systems transfers, and by clinging to ship barges and hulls, which is why clean boating practices are so necessary. This species has also become popular in seafood markets.
The Chinese mitten crab is widespread in the Lower Hudson Valley.
7
Asian shore crab Hemigrapsus sanguineus
TO GUIDE A FIELD Identification http://www.nyis.info/user_uploads/i mages/Asian%20shore%20crab2.jpg The Asian shore crab has a somewhat square carapace with unusual patters and can range in color from brownish orange to greenish black to purple. Each side of the carapace has three distinct anterolateral teeth. The crab also has a light and dark banding pattern on the walking legs. Its claws
have red spots. It can reach 2-3 inches in width. Females are AIS VALLEY’S HUDSON LOWER THE capable of producing three to four clutches per season, each containing up to 50,000 eggs.
Impact
The Asian shore crab Is an opportunistic omnivore and has a very broad diet that can include macroalgae, salt marsh grass, larval and juvenile fish, and small invertebrates. This gives it the potential to affect populations of native crabs, Spread fish, and shellfish by disrupting the food web. It has been known to out-compete native mud crabs, blue crabs, and Originally introduced by release of larvae in ballast water, the Asian lobsters. It occupies habitats very similar to our native mud shore crab continues to spread over great distances because their crabs, overwhelming and dominating their habitat. larvae are suspended in the water for approximately one month before developing into juvenile crabs, allowing the currents to move
Native Range the larvae far away.
The Asian shore crab is native to Russia, Korea, China and The Asian shore crab is approaching the Lower Hudson Valley. Japan.
8
Rusty crayfish Orconectes rusticus
Identification TO GUIDE A FIELD
The rusty crayfish can reach up to 10 cm in length and has robust claws with dark, rusty spots on either side of its carapace. While usually prominent, the rusty colored spots do not develop well in some waters. A rust colored band also appears dorsally down the center of the abdomen. Its greenish color is most
AIS VALLEY’S HUDSON LOWER THE pronounced on its walking legs. Its claws are grayish green to reddish brown and have a black band at the tips.
Impact
The rusty crayfish has a range of ecological impacts on introduced environments that include competition and displacement of native crayfish, increased predation on Native Range snails, native and threatened bivalves, reduction of macrophyte abundance, reduction of sport fish The rusty crayfish is native to Ohio, Kentucky, and Michigan. abundance, reduction of macroinvertebrate abundance, and other cascading trophic interactions. Spread Rusty crayfish reduce sport fish populations by either egg predation or competition with juveniles. It also The most common mode of spread for the rusty crayfish is by anglers displaces native or existing crayfish species, which can using them as bait, or are released by anglers, aquarium hobbyists, and result in less food for fish. commercial harvesters. Females can carry fertilized eggs or a male’s sperm, so a single female can establish new populations.
The rusty crayfish is currently established in the Lower Hudson Valley. 9
Goldfish Carassius auratus
A FIELD GUIDE TO GUIDE A FIELD Identification
Goldfish are small to moderately sized fish with an elongated, stocky body. Wild populations vary in color from gold to olive green to creamy white, and fades to silvery-white along the belly. They have long dorsal fins with 15-21 rays and a hard serrate spine at the origin of
the dorsal and anal fins. Their life span is usually 6-7 AIS VALLEY’S HUDSON LOWER THE years, but can live up to 30.
Impact
Cyanobacteria passing through the goldfish intestine stimulate cyanobacterial growth, which can result in algae blooms. The goldfish is a bottom-sucking feeder Spread which causes the re-suspension of nutrients, leading to algae blooms. Goldfish also prey on the eggs, larvae, Goldfish have been introduced into our waterways through many means. and adults of native fish species. Their feeding method Wild populations have established through the release of pet goldfish. increases water turbidity and decreases the native They are used for ornamental purposes and can escape confinement in aquatic vegetation. Goldfish likely compete with native outdoor ponds. It is thought that the first recorded goldfish release was fish species for habitat and food, eventually displacing the result of an intentional release by settlers wanting to add it to the the natives. North American fish fauna. For a period of time in the 1800s,the US Fish
Commission raised the species and distributed it to many states for Native Range aquaria, fountains, and ornamental lakes. Since then it has been reported in nearly every state. The goldfish is native to central Asia, China, and Japan. The goldfish is currently established in the Lower Hudson Valley.
10
Northern Snakehead Channa argus
A FIELD GUIDE TO GUIDE A FIELD Identification
The northern snakehead has a torpedo-shaped body that tapers toward the tail. They have a single, long dorsal fin, long anal fin, and a small head with a large mouth. They can grow up to 85 cm in length. Resembling a fish with a large mouth and sharp teeth
and a truncated, not rounded tail, the northern
THE LOWER HUDSON VALLEY’S AIS VALLEY’S HUDSON LOWER THE snakehead is easily identifiable by the dark irregular blotches on its sides that lay on top of a golden tan to pale brown body. It can also darken its color to the point of almost obscuring the blotches.
Impact Native Range
If left unchecked, the northern snakehead will expand The northern snakehead is native to China, Russia, and Korea its range and could potentially alter the balance of aquatic ecosystems. The northern snakehead is a Spread voracious feeder of aquatic fauna and can eat prey up to 33% of their own body length. They are capable of The northern snakehead likely entered the United States via pet shops surviving in waters with very low oxygen content, and live fish markets, where they were sold before their threat was giving them a competitive advantage over native realized. Pet owners often unknowingly released them into the wild when they grew too big for aquarium tanks, or as part of religious or cultural
species that require more oxygen. The predatory fish eats numerous species of fish, crayfish, dragonfly practices. larvae, beetles, and frogs. The northern snakehead is currently emerging in the Lower Hudson Valley.
11
Common Carp/Koi Cyprinus carpio TO GUIDE A FIELD Identification
Carp can grow up to 120 cm in length and weigh 60 kg. The common carp is recognized by its small eyes, thick lips, two barbells at each corner of the mouth, large scales outlined in black, and strongly serrated spines in the
dorsal and anal fins. The head is short, with a rounded
THE LOWER HUDSON VALLEY’S AIS VALLEY’S HUDSON LOWER THE snout and toothless, sucker-like mouth. In the wild, common carp are usually olive green to bronze or silver with a pale underside. Koi carp are brightly colored with orange, yellow, white, or black markings.
Impact
Carp are known to damage aquatic macrophyte Native Range populations, which are integral to the ecosystem functioning. They pose a threat to wetlands that are used The common carp is native to Europe in rivers around the Black Sea and as spawning and nursing habitats by native species. They the Aegean basin. can stimulate algal blooms by increasing nutrient release from sediments and decreasing algal grazing by Spread cladocerans. Carp negatively affect species abundance and diversity of macrophytes and some macroinvertebrates, Common carp were introduced to the United States both deliberately in
which can lead to declines in biodiversity. Carp stir up an attempt to imitate the European environment, and accidentally sediment during feeding which results in siltation and through escaping ornamental or aquaculture fish. It has been introduced bioturbidity. They can often drive native species out by worldwide as a food fish in temperate freshwaters. Anglers sometimes overtaking their habitats and can outcompete native use juvenile carp as bait. species and eat their eggs. They can also destroy the native vegetation. The common carp is currently widespread to the Lower Hudson Valley. 12
Oriental Weatherfish Misgurnus anguillicaudatus
TO GUIDE A FIELD Identification
The Oriental weatherfish varies in color from brown to yellow with greenish, grey-brown, or black marbling. The eel-like body is long, laterally compressed, reaching about 15 cm with a maximum length of 30 cm. Its small, narrow mouth is subinferior with 10 barbels.
Four of these barbells are smaller and placed below the VALLEY’S HUDSON LOWER THE lip. It has thick, fleshy lips. Pectoral fins are triangular with a stout spine. It has a dark spot on the upper half of the base of the caudal fin. (9 dorsal rays, 6-7 pelvic rays, 7-8 anal rays).It gets its name as “weatherfish” because it becomes more active in response to changes in barometric pressure. Native Range
Impact Oriental weatherfish are native to Cambodia, China, Hong Kong, India, Japan, Korea, Russia, Taiwan, Thailand, and Vietnam. Oriental weatherfish can cause significant reductions in macroinvertebrate numbers and biomass. It has been Spread associated with elevated ammonia, nitrate/nitrite, and turbidity levels – similar to the water quality impacts of The original means of introduction is through escaped fish farms. The AIS carp. The Oriental weatherfish impacts native fisheries Oriental weatherfish is a common aquarium fish and is popular in the by reducing populations of their macroinvertebrate aquarium trade. It is also spread through its use as live bait. Eggs are not prey, by competing for shelter and spawning sites, and guarded and scatter in open water, allowing currents to take the fish to by preying on eggs and juveniles. It is a highly adaptive new, previously uninvaded bodies of water. species with high competitive ability, high reproductive capacity, high survivorship, and high dispersal ability. The Oriental weatherfish is currently emerging in the Lower Hudson Valley. 13
Round Goby Neogobius melanostomus
A FIELD GUIDE TO GUIDE A FIELD Identification
The round goby is a small, soft-bodied fish readily distinguished from other freshwater fish in North America by the presence of a fused pelvic fin that forms a suction cup shaped fin on the ventral surface. It has a brownish gray body with dark brown lateral
spots. There is usually a large, oblong black spot AIS VALLEY’S HUDSON LOWER THE present at the end of the dorsal fin. The head length is about 23% of the total body length. Spawning males can turn almost solid black. Their soft body and large round head have frog-like raised eyes. This fish can grow 10-25 cm long. Native Range Impact The round goby is native to Asia and parts of Europe. The round goby is thriving and harming the native sport fish populations. It is able to outcompete the native Spread species including lake trout, sculpin, and logperch for food sources, habitat, and spawning sites. It spawns The round goby was introduced to the Great Lakes through ballast water more frequently than other species and feeds on their on cargo ships. They are mistaken with some common baitfish, so boaters eggs and young juveniles. and fisherman can unknowingly carry them from one body of water to
another in bait buckets, bilge water, and more.
The round goby is currently a threat to the Lower Hudson Valley.
14
Sea Lamprey Petromyzon marinus
Identification GUI A FIELD
The sea lamprey is eel-like and has long, flexible, cylindrical, scaleless bodies with a deeply notched dorsal fin that separates it into two distinct parts. It can reach 50 cm in length. It has no scales and no paired fins. Adult sea DE TO lampreys have a disc-like mouth that contains circular rows of over 100 sharp, hooked teeth. Adults can be olive-brown,
yellow-brown, green, red, or blue mottled with darker AIS VALLEY’S HUDSON LOWER THE shades of the same color, or nearly black. The underside is typically white or grey.
Impact
Sea lampreys attack and are parasite feeders on other fish, which often results in the death of the fish. They can destroy Spread up to 40 pounds of fish during their adult lifetime. Typically, only one out of seven fish attacked by a sea lamprey will The sea lamprey appeared in Lake Erie in 1921 via the Welland survive. The population explosion in the 1940s and 1950s canal, and took 25 years to spread to the remaining Great Lakes. contributed significantly to the collapse of economically Larval lampreys are used as bait in non-native areas. Adults can important Great Lakes fish species. attach themselves to boats going through the canal systems, allowing it to travel to previously uninvaded areas. The sea Native Range lamprey also travels over long distances while attached to other
fish. The sea lamprey is native to the east coast of North America, the Northeast Atlantic coast from Norway, Iceland, and the The Sea lamprey is native to the Hudson River and has not Barents Sea, to northern Africa, and the western been found to cause a problem. It is an ecological threat to Mediterranean Sea. non-native areas, including the Great Lakes and Lake Champlain. 15
Fanwort Cabomba caroliniana
Identification TO GUIDE A FIELD
Fanwort is a submersed freshwater perennial plant. It can be found rooted or as floating fragments that can survive up to eight weeks. The branching stems have reddish- brown hair and can grow 6 meters or longer, growing from the rhizomes below the sediment. The submerged leaves are divided into fine branches, giving it a feathery
appearance. Leaves are oppositely arranged, green, and AIS VALLEY’S HUDSON LOWER THE about 5 cm in diameter. Floating leaves are narrow, small and oval or diamond shaped arranged in an alternating pattern. Flowers are small and range in color from white to pink to purple, with a diameter of less than 1.5 cm.
Impact
Fanwort is a very competitive plant, giving it the Native Range opportunity to form dense stands and reduce sunlight for and crowd out previously well-established, native species. Fanwort is native to southern Brazil, Paraguay, Uruguay, and northeast These monocultures are bad for biodiversity and can Argentina. affect the water quality. When large mats of the vegetation die off, their decomposition causes oxygen Spread reductions. This plant can also clog drainage canals and freshwater streams, which impedes recreational and Fanwort has spread through both intentional and unintentional agricultural uses. releases in the aquarium trade. This species is capable of reproducing vegetatively through fragmentation, allowing it to spread via *Commonly mistaken for native Coontail (Ceratophyllum hitchhiking on boats, trailers, and other recreational equipment. demersum) Fanwort is currently emerging in the Lower Hudson Valley. 16
Brazilian Waterweed Egeria densa
Identification TO GUIDE A FIELD
Brazilian waterweed is a freshwater perennial with bright green stems and leaves with short internodes which gives the plant a leafy appearance. Leaves are minutely serrated and linear, 1-3 cm long, and up to 5 mm wide. The leaves are found in whorls of 4-8, but the lowest leaves are opposite or in whorls of 3. Stems are erect, cylindrical, simple or branched, and grow until
they reach the surface of the water where they form dense AIS VALLEY’S HUDSON LOWER THE mats.
Impact
This species forms monospecific stands that can restrict water movement, trap sediment, and cause fluctuations in water quality. The monospecific stands push out native species, reducing the biodiversity of the area. Introduced worldwide through the aquarium trade, even in its native range it becomes a nuisance species and causes economic impacts. Spread Dense beds can interfere with recreational water uses including boat navigation, swimming, fishing, etc. Fragments of the plant Brazilian waterweed has spread via aquarium and water garden can also break off and clog intake structures of water treatment releases. It is only able to reproduce vegetatively by plant plants. fragments which hitchhike on boats, trailers, and equipment and spread to new waterbodies. Brazilian waterweed has the ability Native Range to cover 100 acres of water per year.
Brazilian waterweed is currently emerging in the Lower Hudson Brazilian waterweed is native to South America. Valley.
17 *Commonly mistaken for Hydrilla and native Elodea Hydrilla Hydrilla verticillata
A FIELD Identification
Hydrilla is a submerged aquatic perennial with heavily branched stems towards the water surface. The plant can grow in depths
of up to 30 feet, growing up to a foot per day. The northern TO GUIDE biotype, monoecious hydrilla, mats the floor, creating a “shag rug” look. When the water is warm enough, the hydrilla grows vertically towards the surface, creating dense mats that block the sunlight for native species below. Leaves are strap-shaped
THE LOWER HUDSON VALLEY’S AIS VALLEY’S HUDSON LOWER THE with pointed tips and serrated edges, growing in whorls of 4-8 (usually 5). Leaf color can vary from green, translucent, yellow, to brown.
Impact homes. Large mats of hydrilla can break off and clog water intakes at Hydrilla can impact the ecology and economy in numerous plants, which can be expensive to fix. ways. When hydrilla mats the surface, it blocks sunlight for Native Range native species below it, displacing them and forming a monoculture. Hydrilla can grow up to a foot each day, easily The dioecious plant (found in the south) is native to southern India, and overtaking large bodies of water. It can thrive in many water the monoecious plant is native to Korea. Both species are not found on types, ranging from stagnant or moving, freshwater to brackish every continent except Antarctica. water, high or low sunlight, high or low nutrient levels, etc. It also creates tubers that remain viable under the sediment for Spread up to 10 years, making treatments or removals more difficult. Hydrilla can spread vegetatively through fragmentation, making it a When large mats of hydrilla die later in the season, algae potential hitchhiker on boats, trailers, and other equipment. It can also blooms can be created, causing fish kills. Hydrilla is also a host spread via turions, or overwintering buds, that can flow downstream and to a species of cyanobacteria that has caused deaths of at least start new populations. Hydrilla also produces tubers, which are potato-like 99 bald eagle and thousands of American coots. structures that lay a few inches below the sediment. These can remain Hydrilla can also devastate recreational activities including viable for up to 10 years, making hydrilla management projects more swimming, boating, fishing, and more, which can harm tourism difficult. industries. Hydrilla infestations also lower the value of waterfront Hydrilla is currently emerging in the Lower Hudson Valley. 18 *Commonly mistaken for Brazilian waterweed and native Elodea
Parrot-feather Myriophyllum aquaticum
A FIELD GUIDE TO GUIDE A FIELD
Identification
Parrot-feather is named for the feather-like leaves arranged around the stem in whorls of 4-6. It has both emergent and submerged aquatic leaves and can easily be mistaken for Eurasian watermilfoil. The submersed leaves are 1.5-3.5cm long with 20-30 divisions per leaf.
Emergent leaves are 2-5 cm long with 6-18 divisions per AIS VALLEY’S HUDSON LOWER THE leaf. The bright green emergent leaves are stiff and darker green than the submersed. The emergent stem and leaves can grow up to a foot above the water and look almost like a small fir tree. Submersed leaves are limp and appear to be decaying with very robust stems.
Native Range Impact
Parrot-feather is native to South America. Parrot-feather has been introduced worldwide as an aquarium plant. It can spread vegetatively via fragmentation and can alter the physical and chemical Spread characteristics of a lake or stream once established. Infestations can shade out the algae in the water In the United States, there are only female parrot-feather plants, so it is column that serve as the basis of the aquatic food web. restricted to spreading vegetatively through fragmentation. This means It is also good habitat for mosquito larvae. Parrot- it can easily spread as a hitchhiker on boats, trailers, and other feather can also restrict recreational opportunities and equipment that comes into contact with the water. activities in the infested bodies of water. Parrot-feather is currently a threat in the Lower Hudson Valley.
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Variable leaf/Broadleaf milfoil Myriophyllum heterophyllum
TO GUIDE A FIELD Identification
Variable leaf milfoil is a submersed aquatic plant with emergent flowering spikes. Submerged leaves are feather- like, green, 2-5 cm long and 2-4 cm wide, dissected into 7- 11 leaflets and whorls of 4-5. The emergent spike can reach 5-15 cm above the water surface. This species can be very difficult to differentiate from Eurasian watermilfoil and
AIS VALLEY’S HUDSON LOWER THE other milfoil species. The stem of the variable leaf milfoil is sturdier than others, and the submerged leaves are thicker and rougher. Unlike Eurasian watermilfoil, when you pull variable leaf milfoil from the water, it can hold its form.
Impact
Variable leaf milfoil is an aggressive plant that can grow up to one inch per day. It can form dense vegetative mats and reduce water movement. When decomposing, it reduces water quality and available oxygen which can harm fish and Spread other aquatic organisms. The thick mats often outcompete native vegetation. It can also clog boat motors and deter This species of milfoil primarily spreads vegetatively through people from water related activities. fragmentation, which are able to hitchhike on boats, trailers, and other equipment. Currents are also able to move fragments long Native Range distances. Variable leaf milfoil is native from southwestern Quebec and Ontario to North Dakota and southward to New Mexico Variable leaf milfoil is currently emerging in the Lower Hudson and Florida. Valley.
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Eurasian watermilfoil Myriophyllum spicatum
TO GUIDE A FIELD
Identification
Eurasian watermilfoil is an aquatic perennial, dicot herb with long branch stems and feather-like whorled leaves. Its small reddish flowers emerge from the water on a spike. Stems are slender and smooth, reaching up to 6 m long and range in color from reddish-brown to
whitish-pink. The leaves are olive green and are typically AIS VALLEY’S HUDSON LOWER THE less than 5cm long. Each leaf is soft, deeply divided and feather-like, and can be found in whorls of 3-6 (usually 4). A distinguishing feature of Eurasian watermilfoil is the end of each leaf, as the leaf divisions end in almost a straight, horizontal line rather than coming to a point (see top left picture). Native Range
Eurasian watermilfoil is native to Europe, Asia, and northern Africa. Impact
Eurasian watermilfoil grows in dense patches, forming a Spread monoculture which shades out native species. It is less of a food source than the natives that it replaces, and Eurasian watermilfoil does not rely on seeds for reproduction. Instead, it supports fewer insects that serve as the food resources reproduces vegetatively via fragmentation. These fragments break off for fish. Predatory fish lose foraging space and are less and float long distances with water currents. Fragments can also be efficient at obtaining prey in infested areas. When large transported long distances by hitchhiking on boats, trailers, and
mats of the plant decay, oxygen levels drop, altering the equipment. ecosystem. Dense mats of Eurasian watermilfoil also impede water movement and limit recreational Eurasian watermilfoil is current widespread in the Lower Hudson Valley. activities
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Brittle Naiad Najas minor
TO GUIDE A FIELD Identification
Brittle naiad is a submersed, annual herb with compact, bushy growth. Stems can reach up to 2.5 m long and are abundantly branched near their apex. Its leaves are opposite, but can appear to be in a whorl at the tip. The leaves can grow 1-2 inches long, and are toothed, stiff, curved, and pointed. Its flowers are inconspicuous. As
stated in the name, this species is very brittle and easily AIS VALLEY’S HUDSON LOWER THE breaks into pieces.
Impact
Brittle naiad is able to establish dense monocultures, Republic, France, Germany, Hungary, Italy, Poland, Portugal, excluding other native vegetation and affecting fish and Romania, Siberia, Ukraine, Morocco, India, Turkey, and Japan. waterfowl biodiversity. Unlike many other aquatic invasive plants, brittle naiad does not produce long stems that Spread spread on the surface of the water. But its dense monocultures still capable of interfering with recreational Brittle naiad can reproduce vegetatively through fragmentation. activities like swimming, boating, and fishing, and can These fragments can hitchhike on boats or other equipment and be reduce the aesthetic appeal of the waterbody. Brittle naiad transported to a previously uninfested body of water and start new can also reduce the discharge capacity of channels as well. populations. Waterfowl also spread the species by ingesting the seeds and excreting them in new locations. Wind and currents can Native Range pull fragments of brittle naiad to new locations, where the viable fragments can establish new infestations. Brittle naiad is native to Austria, Belgium, Bulgaria, Czech While not prohibited, brittle naiad is considered invasive and is established in the Lower Hudson Region. 22
Curly-leaf pondweed Potamogeton crispus
A FIELD GUIDE TO GUIDE A FIELD Identification
Curly-leaf pondweed is a submerged perennial plant with oblong, reddish-green to translucent, wavy, alternate leaves with finely toothed margins. Leaves are 0.5-1.5 cm wide and 3-10 cm long. Stems are branched and somewhat flat. The plant can reach 1 m in height. The plant flowers
and fruits in late spring to early summer. When it dies off, it leaves fruits and turions to survive the summer. The AIS VALLEY’S HUDSON LOWER THE turions produce new, small plants that overwinter.
Impact
This pondweed is able to tolerate low light levels and temperature conditions, allowing it to grow sooner than native plants. Curly-leaf pondweed can grow in very dense Spread beds that can outcompete native plants, creating a monoculture. Dense surface mats can disrupt recreational This pondweed produces burr-like overwintering buds called activities. It can spread through fragmentation. Curly-leaf turions that can spread long distances with the current, pondweed can increase algal blooms, decreasing the allowing it to reproduce vegetatively. Curly-leaf pondweed also aesthetic value of waterfront properties. It can reduce the produces seeds and can be spread by waterfowl ingesting fetch of a lake and can stratify the water column in them. Fragments can also spread on recreational equipment normally unstratified systems. including boats and trailers.
Native Range Curly-leaf pondweed is currently established in the Lower
Curly-leaf pondweed is native to Eurasia, Africa, and Hudson Valley. Australia.
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European Frogbit Hydrocharis morsus-ranae
A FIELD GUIDE TO GUIDE A FIELD
Identification
European frogbit is an herbaceous, annual aquatic that can reach 20 cm in length. It is a free-floating plant whose leaves are usually floating, but can be emergent if the vegetation is dense enough. The leathery, glabrous leaves are cordate-orbicular in shape
measuring about 1-6 cm in length and width. The lower AIS VALLEY’S HUDSON LOWER THE leaf circle is dark purple. European frogbit resembles a quarter-sized lily pad.
Impact
European frogbit can impede water flow in irrigation systems and canals, and lessen recreational and Native Range aesthetic values on waterfront properties. This can lead to a decrease in tourism. European frogbit is native to Asia and Europe. Dense monocultures and mats of European frogbit block light penetration in the water column, reducing Spread available light for native species. They can also deplete oxygen levels by limiting water circulation and increasing decomposition of dead plants, which European frogbit can spread both vegetatively and by turions. Spreading changes the water quality and affects the ecosystem. vegetatively, or by fragmentation, allows frogbit to spread as a hitchhiker on boats and trailers. It also grows turions, which float to the surface and grow in the spring. A single plant can produce 150 turions each season.
European frogbit is currently a threat in the Lower Hudson Valley.
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Yellow floating heart Nymphoides peltata
GUIDE A FIELD Identification
The yellow floating heart is a perennial, water lily-like plant that mats the surface of the water with long stalked, heart-shaped leaves. The leaves are 3-10 cm long, and are usually purple underneath. It has a showy, five petaled yellow flower growing on long TO stalks and rising a few inches out of the water. There AIS VALLEY’S HUDSON LOWER THE can be multiple flowers per stalk. The flower edges are distinctively fringed.
Impact
The yellow floating heart can grow very dense patches and displace the native species. The plants can also limit movement in the water column, creating stagnant areas with low oxygen levels below the floating mats. Dense patches can hinder recreational activities including boating, swimming, and fishing. Spread Native Range Originally introduced as an aquatic ornamental for outdoor water
The yellow floating heart is native to Asia and Europe. gardens, it continues to be spread accidentally through outside water gardens. The hairs on the seeds also allow the seeds to attach to waterfowl, which can also spread the plant.
Yellow floating heart is currently a threat in the Lower Hudson Valley. 25
Water chestnut Trapa natans
Identification TO GUIDE A FIELD
Water chestnut is a rooted, floating plant. Its floating leaves are arranged in rosette. The individual leaves are 2 -4 cm long and are sharply dentate along the leaf margins. The lower surface has conspicuous veins and short, stiff hairs. Submerged lower leaves are alternate and feather like and can reach 15 cm in length. The fruit
is a four-horned nut-like structure about 3 cm wide and AIS VALLEY’S HUDSON LOWER THE develop underwater.
Impact
Water chestnut can completely mat the surface, causing competition with native species for light, nutrients and space. When it decomposes, it can lower dissolved Spread oxygen levels which can lead to fish kills. It has little value for waterfowl. The spiny fruit can hurt people and Water chestnut produces nut-like seeds that germinate in the spring, and animals when stepped on. Big infestations can impede each seed is capable of producing 10-15 rosettes. Each plant is capable of recreational activities and commercial navigation. producing 20 seeds per season. These seeds sink to the bottom and are able to remain viable for up to 12 years. This plant also spreads Native Range vegetatively through fragmentation. Fragments are able to spread on boats, trailers, and other equipment. Water chestnut is native to Europe, Asia, and Africa. Water chestnut is currently established in the Lower Hudson Valley.
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Yellow Iris Iris pseudacorus
A Identification TO GUIDE FIELD
Yellow iris is a perennial monocot that forms dense stands in waters up to 25 cm deep. It can grow between 40-150 cm tall. Its rhizomes are 1-4 cm in diameter with roots up to 30 cm long. The leaves are broad up to 100 cm long and 30 mm wide with a raised midrib, and comes to a fine
point. Flowers are yellow and 8-10cm in diameter. AIS VALLEY’S HUDSON LOWER THE
Impact
The yellow iris thick rhizomes create a sort of mat that prevent the germination and seedling growth of other plant species. This can also congest water flow. They also change the ecosystem by compacting soil and elevating the Native Range topography, creating a drier habitat with increased rates of siltation and sedimentation. It is a fast growing, fast Yellow iris is native to Africa, Asia, and Europe. spreading plant that can outcompete other native wetland species and form impenetrable thickets. This species is poisonous, harming fish and animals that Spread touch or eat it. It is capable of causing skin irritation to humans. The yellow iris can reproduce vegetatively through underground stems, or rhizomes, which form into roots and allow it to re-grow new plants
each season.
Yellow iris is currently emerging in the Lower Hudson Valley.
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Purple loosestrife Lythrum salicaria
A FIELD GUIDE TO GUIDE A FIELD Identification http://kboo.fm/sites/default/files/nodeimages/ purple_loosestrife_oaks_bottom.jpg
Purple loosestrife is an erect perennial herb with a woody four- sided stem. Leaves are generally whorled and opposite, lance- shaped but heart-shaped or rounded at the base. Mature plants can have up to 50 stems emerging from a single rootstock. The plant can grow from 1.2-3 m. Showy, magenta-colored flowers with 5-7
petals.
THE LOWER HUDSON VALLEY’S AIS VALLEY’S HUDSON LOWER THE
Impact
Purple loosestrife can outcompete and replace native grasses, sedges, and other flowering plants that provide higher quality food sources and habitat. It forms dense monocultures that restrict native wetland plant species and can overrun wetlands to almost http://www.nps.gov/plants/alien entirely eliminate open water habitat. Recreational and aesthetic /fact/lysa1.htm values of wetlands and waterways are diminished when dense stands come in and decrease biodiversity. Purple loosestrife can also alter decomposition rates and nutrient cycling and water chemistry. Spread Native Range Purple loosestrife has a very long flowering season, allowing
it to produce two to three million seeds each year from its Purple loosestrife is native to Eurasia, Britain, central and southern 30-50 flowering stems. It also produces vegetatively through Europe, central Russia, Japan, China, southeast Asia and northern underground stems, or rhizomes. India.
Purple loosestrife is current widespread in the Lower
28 Hudson Valley.
Phragmites/Common Reed Phragmites australis
TO GUIDE A FIELD Identification
Phragmites is a tall, perennial grass with erect, rigid, smooth, and hollow culms that can be 2.5 cm in diameter and up to 4 m tall. The culms terminate in dense, 30 cm long panicles. The leaves are typically 25-50 cm long and 1- 4 cm wide. Phragmites has an extensive rhizome network and roots that grow at depths of 1 m. The feathery flower
head is 13-40 cm long and is composed of many long AIS VALLEY’S HUDSON LOWER THE branches that point upwards.
Impact
Phragmites is a vigorous growing plant capable of turning biodiversity rich habitats into dense monotypic stands that overtake available growing space and push out native species. It alters wetland hydrology and can increase the potential for fire. It also reduces and degrades wetland Spread wildlife habitat because of its dense growth habit, which can reduce the biodiversity. It is capable of changing the Phragmites spreads vegetatively through rhizome and stolon marsh hydrology by decreasing salinity in brackish fragments. Rhizomes can break off and can be moved downstream wetlands, changing the topography, and outcompeting through the currents, establishing in previously uninfested areas. other plant species. Fragments can also spread via machinery. It also produces wind-
Native Range dispersed seeds, but this seed viability is low.
Originally from Europe, Phragmites is now found on every Phragmites is currently widespread in the Lower Hudson Valley. continent except Antarctica, and is even encouraged to grow in some regions, particularly in eastern Europe.
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Native Lookalikes American waterweed/Common Elodea Coontail/Hornwort Elodea canadensis Ceratophyllum demersum
Native elodea is commonly mistaken for hydrilla and Brazilian Native coontail is a submersed plant found in all 50 states, including waterweed (and vice versa). While these species may look very many New York lakes and ponds. It is commonly mistaken for the similar, they have extremely different effects on the ecology. It is invasive plants Eurasian watermilfoil and fanwort. Its serrated, important to note the distinguishing differences between the forked leaves are arranged in whorls around the stem, with 5-12 species. leaves per whorl. It is somewhat hard and crusty when held. When Elodea, often thought of as the typical aquarium plant, can be pulled out of the water, coontail holds its form pretty well, which is identified by its: a distinguishing characteristic that allows us to differentiate it from 3 leaves/whorl (occasionally 4) fanwort and Eurasian watermilfoil Visibly smooth leaf margins (finely toothed under a microscope) Purple tint on stem below each whorl NO tubers
.
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The Field Guide Sources
The following sources were used for multiple species: Spiny Water Flea 1. Pennsylvania’s Field Guide To Aquatic Invasive Species. 1. New York Invasive Species Information Pennsylvania Sea Grant
The Field Guide Sources Cont. Image Credits
Curly Leaf Pondweed Overview 1. Potamogeton crispus (curlyleaf pondweed). Invasive Species 1. Main picture: Compendium
Image Credits Cont.
Spiny Water Flea Northern Snakehead 1.
Image Credits Cont.
Fanwort Eurasian Water Milfoil 1.
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Water Chestnut 1.
This project was contracted by the Lower Hudson Partnership for Regional Invasive Species Management using funds from the Environmental Protection Fund as administered by the New York State Department of Environmental Conservation.
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